383 build

[b.cowling]

i was disassembling my motor for a 350 build and i found a lot of things that i did not expect first cam bearings shot and also crank main bearings were pretty bad so was thinking should i keep 350 crank and get it repolished or i found a 400 crank with new 400 connecting rods, new flywheel, and damper for $50. crank mains need grind anyway so was thinking 383 old style 400 crank turned down, 400 connecting rods with 350 pistons. is this a good idea.
thanks

[Grumpy_old_fart]

oy

[RAGAN]

Only if its all cast

[Grumpy_old_fart]

ok... before you dream yourself into a 383..

have the 400 crank magnafluxed.

itll be cracked.

so, throw your 40 bucks away with the crankshaft.

then, you gotta buy another one... my bet is that youre gonna go with a cast stroker crankshaft that will cost less than the balance job its gonna need.

dont run 400 rods. they will try to shove the piston through the cylinder wall. use a 6 inch rod, you will be happier... only about 300 bucks for rods.

this means you will need new pistons... another 300-700 bucks.

your stock heads wont feed it worth a shit, so you will want to step up to a decent set of heads. 700-1400 bucks.

1 5/8 headers bring the suck on something like this, again, it has to breathe..
headers are 275 bucks for 1 3/4 tubes.

you can run whatever intake you want, the best bang for the buck is the weiand stealth intake.

induction... big can of worms.... anything can be adapted to fit the weiand, so either tbi/carb will work, but tbi units for small blocks only flow about 500 cfm... this limits your hp capability, because it cant breathe... you need about 750cfm.

the reason your existing engine died? cam went flat, the pieces of metal that came off the flattened lobe went through the motor and ruined the crank.

so, upgrade to a hydraulic roller cam, retrofit style will run about 230 for the cam, 200-500 for lifters, 100 bucks for springs, 50 for steel retainers 100 for titanium, new shorter pushrods will cost you between 40 and 200 bucks, depending on who you get them from.

you will need an oil pump, a timing chain, gasket set, and about 1000 bucks worth of little shit to make it new again.

still sound like a good deal?

or, you can have your 350 crank ground 10 under on rods and mains, buy new bearings, rings, gaskets, cam, lifters, timing chain and gears, oil pump, and 1000 bucks worth of little shit to make it run again, only to have the cam go flat in 2-3 years...



so... which one is your best choice?

[jd350az]

why does the "cam go flat"? never heard that

[Grumpy_old_fart]

Todays oils have been reformulated to comply with EPA guidelines. The EPA has mandated the lowering of the phosphorous and Zinc contents to almost minimal levels.

the scrubbing of the lifter on the cam lobe requires additives such as zinc and phosphorous to keep the cam and lifter alive. anytime you change your oil in an older style engine that has flat tappet lifters, you should add some break in additive.

or not.... and rebuild the motor every couple of years.

or, the smarter way would be to upgrade to roller stuff...

[b.cowling]

ya i think ill just stay with 350 crank then. trying to keep it in a budget already bought everything for my 350 build but was thinking since my crank needs grinding i was looking at used cranks and found this crank cheap i would maybe do that and have a stroker. this motor is not going be used often at all trailered to friends farms, some trails, mud bogs. 383 would also get me exactly what i wanted for power but dont really want to buy a whole 383 kit im in canada so everything costs nearly double by the time its shipped. how do you know its cracked is it common for 400 cranks to be cracked heres the ad http://ontario.kijiji.ca/c-cars-vehi...AdIdZ336667508
thanks for the responses

[Grumpy_old_fart]

It is thought that all 400 crankshafts are cracked from the factory... friends of mine at different machine shops all complain about "Every factory 400 crank they have ever seen are cracked"....

and people think its a good idea to spend 200 bucks on machine work to turn the journals down on a cracked crank instead of buying a 500 dollar crank that will survive.

[jd350az]

What years did they start being upgraded from the factory because I still see small block chevies with 300k on them driving around using cheap oil and cheap gas hehe. The 383 was one thing I was looking at doing to my suburban when I got the time. Wanted to pick up another 350 motor and go through it and upgrade to the 383 stroker and freshen everything up, etc then swap it for my TBI 350. You can upgrade the TBI to handle the 383 can't you?

[Grumpy_old_fart]

Originally Posted by jd350az

What years did they start being upgraded from the factory because I still see small block chevies with 300k on them driving around using cheap oil and cheap gas hehe. The 383 was one thing I was looking at doing to my suburban when I got the time. Wanted to pick up another 350 motor and go through it and upgrade to the 383 stroker and freshen everything up, etc then swap it for my TBI 350. You can upgrade the TBI to handle the 383 can't you?

the largest factory tbi is from a 454, it is rated at 600cfm. wiring is different, but easily fixed.

still to small for anything over 5000 rpm.

roller lifters were available after 1987 in one piece rear main blocks. the nice thing about a 1 pc rear main block is that they will take a 3.875 stroke crank without major machining. This will get you 395 cubic inches with a .030 overbore.

1984 and earlier 2pc rear main seal blocks were an issue with any stroke larger than 3.75 because you risk breaking into the oil galley on the lower side of the block or into water if there was any core shift. you have to clearance the block to fit the rod bolts. you can, of course, use small journal crankshafts to get around this, and your cost will show it.

anything (in my humble opinion) running a flat tappet camshaft is on borrowed time, or doesnt have enough spring pressure to pose any concern on wear of the lifters and cam. which means it doesnt really have a lot of performance potential without a change.

[MaxPF]

If you're gonna run a non-roller cam, get some ZDDPlus and add the proper amount with each oil change. Or, you can run oils that already have enough ZDDP in them. Modern CJ-4 diesel oils are barely adequate, since they have had to reduce zinc and phosphorous levels to get DPF's to survive. Future diesel oils will probably be even worse (not sure what those of us with Cummins engines will do, since they are ALL flat tappet, albeit with very low spring loads). A better bet is to use oils designed for flat tappets and high performance engines. Brad Penn Penn Grade 1 is a good one. High end synthetics (i.e. Redline, NOT Mobil 1 or any others made by big oil companies)) also have plenty of AW additives. If you use a high end synthetic you want to extend drain intervals to at least 10,000 miles to get your moneys worth. UOA's are a good idea as well - low iron levels mean the oil is protecting your flat tappet cam.

[1BMFK5]

Spend the money on a 5.3 it will be cheaper, and fuel injected! I just spent $2,000 building a cast crank stock iron headed 383. And I'm using a lot of old parts including headers and all my driven accessories.

[tilley52]

my .02

383's run great if they are built right, i had 7k into a 383 with all forged stuff, AFR heads and a full roller valve train, plus another 2200 in ignition, fuel supply and nitrous and it ran perfect for about 6 years, all i did was take it apart after 3 check every thing out and reassembled with new bearings and rings. turned out just shy of 850 flywheel HP on spray @ 6k. around 540 motor alone.

but you need to spend money to save your self shit in the future plus it will show in the hp numbers.

i have moved on to the fuel injection stuff and the LS based motors have a lot going on for them. its a piece of cake to make 500hp on a 6.0 you can get a complete motor with harness for under 1600bucks. add in some conversion motor mounts converter adapter thing headers and corvette fuel pump. ur prolly around totaling 2k. then the small nickle and dime stuff. and you will have a nice daily driver motor that gets good MPG's and makes 360hp.

later on you can throw 2k at that,,,(all bolt ons) and make mid 500 HPs